Fillings

General Information

 

Fillings

Traditional dental restoratives, or fillings, are most often made of silver amalgam or gold alloy. The strength and durability of this traditional dental material makes it useful for situations where restored teeth must withstand extreme forces that result from chewing, often in the back of the mouth.  Newer dental fillings include ceramic and plastic compounds that mimic the appearance of natural teeth.


These compounds, often called composite resins, are usually used on the front teeth where a natural appearance is important, but they can also be used on the back teeth depending on the location and extent of the tooth decay.  There are two different kinds of fillings: direct and indirect. 


Direct fillings are fillings placed into a prepared cavity in a single visit. They include silver amalgam, glass ionomers, resin ionomers, and composite (resin) fillings. Indirect fillings generally require two or more visits. They include inlays, onlays, and veneers. They are used when a tooth has too much damage to support a filling but not enough to necessitate a crown.


 

Determining If You Need a Filling

Your dentist may use several methods to determine if you have tooth decay (caries), including:

  • Direct Observation — Some discolored spots on your teeth may indicate decay, but not all of them. Your dentist may use an explorer, a metal instrument with a sharp tip, to probe for possible decay. Healthy tooth enamel is hard and will resist pressure by the explorer. Decayed enamel is softer. The instrument will stick in it slightly. Explorers must be used with caution. Pressing too hard with an explorer can damage a healthy tooth. It can also spread the bacteria that cause decay to other teeth. Magnification is also a useful aide.
  • Cavity-detecting dye — This can be rinsed over your tooth. It will stick to decayed areas and rinse cleanly from healthy ones.
  • X-rays — X-rays can show decay developing in the enamel on the sides of teeth where they come together, as well as in the dentin that lies under the enamel. X-rays are often not accurate in detecting smaller cavities on occlusal (top) surfaces. Current fillings or other restorations also may block the view of decay.
  • Laser fluorescence cavity detection aids — These small wands measure changes caused by caries. They are especially useful for pit and fissure areas on the top surfaces of your molar and premolar (chewing) teeth.

 

Decay is not the only reason you may need a filling. Other reasons include:

  • Cracked or broken teeth
  • Teeth that are worn from unusual use, such as:
    • Nail-biting
    • Tooth grinding (bruxism)
    • Using your teeth to open things

Steps to a Filling

When you visit your dentist to get a filling, you may be given local anesthesia (LA) to numb the area if necessary. Next, your dentist will remove decay from the tooth, using a drill. Lasers also can be used to remove decay but are generally much slower.

A drill, which dentists call a handpiece, uses metal cones called burs to cut through the enamel and remove the decay. Burs come in many shapes and sizes. Your dentist will choose the ones that are right for the size and location of your decay.

At first, your dentist will use a high speed drill (the one with the familiar whining sound) to remove the decay and unsupported enamel of the tooth. Once the drill reaches the dentin, or second layer of the tooth, the dentist may use a lower speed drill. That's because dentin is softer than enamel.

Once all the decay is removed, your dentist will shape the space to prepare it for the filling. Different types of fillings require different shaping procedures to make sure they will stay in place. Your dentist may put in a base or a liner to protect the tooth's pulp (where the nerves are). The base or liner can be made of composite resin, glass ionomer, zinc oxide and eugenol, or another material.

Some of these materials release fluoride to protect the tooth from further decay.

If your dentist is placing a bonded filling, he or she will etch (prepare) the tooth with an acid gel before placing the filling. Etching makes tiny holes in the tooth's enamel surface. The composite material fills in the holes as the dentist places the filling. A bonding material also is used, so the filling bonds to the tooth in two ways. Bonded fillings can reduce the risk of leakage or decay under the filling. Bonding is generally done with composite fillings.


 

Certain types of fillings get hardened by a special light. With these fillings, your dentist will layer the material, stopping several times to shine a bright light on the resin. This cures (hardens) the material and makes it strong.

Finally, after the filling is placed, your dentist will use burs to finish and polish the tooth.

After a Filling

Some people feel sensitivity after they receive a filling. The tooth may be sensitive to pressure, air, sweet foods or cold. Composite fillings often cause sensitivity, but other types of filling materials can, too.

The most common reason for pain right after the anesthetic wears off is that the filling is too high. Call your dentist so you can be seen as soon as possible to reduce the height of the filling.

The second type of discomfort is a very sharp shock that appears only when your teeth touch. This is called galvanic shock. It is caused by two metals (one in the newly filled tooth and one in the tooth it's touching) producing an electric current in your mouth. This would happen, for example, if you had a new amalgam filling in a bottom tooth and had a gold crown in the tooth above it.

In most other cases, the sensitivity will decrease over one to two weeks. Until then, try to avoid anything that causes it. If your tooth is extremely sensitive or your sensitivity does not decrease after two weeks, contact your dentist's office.

It's important to let your dentist know about any sensitivity you are feeling. The next time you need a filling, he or she may be able to use a different material and make changes to reduce sensitivity. People vary in their response to different materials. Your dentist has no way of predicting if your tooth will react to a particular material.

When you talk to your dentist about the sensitivity, try to describe it as precisely as possible. This information will help decide what should be done next. Your dentist may take out the filling and put in a new one. He or she may add a base, liner or desensitizing agent on the tooth as well. If the filling was very deep, you could need a root canal treatment to solve the problem.

Your dentist polishes the filling after it is placed, but occasionally sharp edges may remain. You can't detect this at first because of the anesthesia. If you find one, contact your dentist and arrange to have it smoothed as soon as possible to avoid injury to your tongue or mouth.

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